AUGUSTA – Gov. John E. Baldacci said Monday he will require the former owners of the defunct HoltraChem plant to pay about $200 million to truck away 370,000 tons of mercury-contaminated soil from the former Orrington industrial facility.

“Less than a year ago, I promised the public that we would be aggressive about minimizing the risks to public health and environment posed by the long-standing and very toxic contamination on the property,” the governor said. “It’s simply unacceptable to have the highest concentrations of mercury poised on the banks of the Penobscot. We have a terrible toxic legacy commanding our attention and demanding definitive action.”

Speaking with reporters from his State House office, Baldacci and Maine Department of Environmental Protection Commissioner Dawn Gallagher proposed a “bold” plan of action for Mallinckrodt Group Inc., the former St. Louis-based owner of the chemical and pesticide factory that has assumed responsibility for the property.

In a process that’s expected to take four to six years, the Baldacci administration wants Mallinckrodt to move more than 17,000 truckloads of contaminated soil so the site may be redeveloped into a valuable asset for the Penobscot River community. Gallagher said the soil to be removed is located in five landfills on the grounds of the old chemical plant. The soil could be shipped to a treatment facility, possibly in Canada.

Mallinckrodt prefers solutions that would contain the contaminated soil to prevent it from poisoning the air or water. But Gallagher said Monday she was forced to reject those options.

“Clearly the best alternative for future years is to send the soils off-site, away from the Penobscot River, for proper, safe disposal,” she said. “I am sensitive to the fact that it’s the most expensive option, but it does away with lingering doubts that could worry residents and possibly cloud future development.”

Orrington officials, she said, are also on board with the administration’s plan since the town was forced to take the property over in a tax foreclosure after HoltraChem ceased operations five years ago. Seventy-seven of the complex’s 235 river-front acres are contaminated and municipal officials would like to redevelop as much of the land as possible.

Gallagher said cleanup operations to date have been funded by Mallinckrodt. The company never operated at the site, but, as a former owner of the property, it is the last remaining company capable of undertaking the remediation. Expenses to date are estimated at more than $11 million.

Sarah Kramer, a spokesperson for Mallinckrodt, said Monday her company rejected the administration’s proposal in favor of other alternatives the firm deemed more practical than the course of action recommended by the DEP.

“While we don’t agree with the option outlined by Gov. Baldacci, we will continue to partner with the DEP and [federal Environmental Protection Agency] to identify a definitive course of action and will comment at any public meetings regarding this recommendation in the near future,” she said.

Kramer said her company favors a proposal advanced by an independent environmental management firm, Camp Dresser & McKee, that involves the containment of the contaminated soil.

“This option is scientifically sound and a significantly less disruptive method for site cleanup,” she said. “Additionally, if this alternative method is adopted, less mercury air emission will be generated through the cleanup and the entire process could be completed in less time.”

“To me, if you’re going to move it around, you might as well move it off the property and deal with it once and for all – that really makes the most sense,” Baldacci countered.

At the time of her morning meeting with reporters, Gallagher said her office now plans to issue a draft decision and then hold a public meeting to collect reactions to the proposal before reaching a final decision.

“I hope they [Mallinckrodt] decide that this is the right way to move forward,” Gallagher said. “If they don’t, there are appeal rights. Certainly $200 million is a lot of money, but as the governor said, it’s the only permanent solution.”